condition mean min max ZT0-3 2.5962199999999998 2.415945 2.776495 ZT4-7 2.1388 2.1388 2.1388 ZT8-11 1.275105 1.275105 1.275105 ZT12-15 0 0 0 ZT16-19 2.808955 2.808955 2.808955 ZT20-23 2.66934 2.66934 2.66934